In this study, we plan to begin a systematic examination of the feasibility of using selected biochemical markers from the gingival crevicular fluid (GCF) to monitor orthodontic treatment. The markers we have chosen to study are enzymes widely used to monitor connective tissue turnover (including bone): acid phosphatase and tartrate-resistant acid phosphatase (TRAP) for bone resorption, alkaline phosphatase for bone formation and matrix metalloproteinases for general connective tissue breakdown. Our specific aims are as follows: 1. To measure longitudinally alkaline and acid phosphatase (including TRAP) activities in the gingival crevicular fluids of subjects having orthodontic treatment and matched controls. 2. To assess qualitative changes in the types of matrix metalloproteinases prevalent in the gingival crevicular fluid of subjects having orthodontic treatment and matched controls. The subjects will be drawn from two- hundred and seventy patients who will be completing the early treatment phase of a randomized prospective clinical trial of class II treatment (DE 08715). During the next year they will be assigned to treatment with fixed appliances or observation based on need and desire for further correction. Our protocol on the trial also calls for data collection at the beginning and end of treatment and yearly for three years. Data collected at these items will include the following; study models, cephalograms, panoramic radiographs, intraoral and extraoral photographs, hand-wrist radiographs, craniomandibular index, gingival index, plaque index, and various psychological instruments designed to assess attitudes toward treatment, satisfaction with results and psychosocial adjustment. In the present protocol, we plan to collect gingival crevicular fluid from two intraoral test sites (one anterior and one posterior) at monthly adjustment visits. In addition, we also plan to assess gigival health at these sites monthly by doing gingival and plaque indices. Tooth movement will be assessed at the anterior site by measuring overbite, overjet and irregularity of contact points. Tooth movement will be assessed at the posterior site by interarch relationship at the occlusal plane.